Crystal Structures and Conductivities of Two Organic–Inorganic Hybrid Complexes Based on Poly‐Keggin‐Anion Chains

Abstract

Two proton-conducting organic-inorganic hybrid complexes have been constructed by the self-assembly of protonated water clusters, transition-metal aqua ions, [PMo 12 O 40 ] 3-anions and isonicotinic acid N-oxide (HINO). Single-crystal X-ray diffraction analyses at 293 K revealed that both complexes presented exactly the same three-dimensional supramolecular framework built from non-covalent interactions. Interestingly, the [PMo 12 O 40 ] 3-anions self-assembled into poly-Keggin-anion chains in the supramolecular frame-

Proton conductive watery channels constructed by Anderson polyanions and lanthanide coordination cations

“…32 Since then, developments on the conductivity of POMs have concentrated upon transition metal-substituted heteropolyacids (HPAs) and POM-MOFs. 30,31,[33][34][35][36][37][38][39] In these compounds, conductivity generally arises from guest water and coordinated water as proton donors or carriers; furthermore, it could also be caused by the characteristics of a "pseudoliquid phase" with high proton mobility. However, HPAs are watersoluble, and non-definition of determined proton transfer pathways limits their development in high proton conduction.…”

“…[40][41][42][43] As transferable inorganic building blocks, POMs have been applied in the preparation of functional materials based on ionic networks. 38,39,43 The solubility and aggregation state of POM-based ionic crystals can be finely tuned by the choice of sizes, shapes, charges, and ligands of the constituent ions. 40 Polyanions and macrocations can form hydrophilic channels in ionic crystals by strong electrostatic forces, which is suitable for accommodating guest molecules in the crystal lattice.…”

“…However, there are limited reports of POM-based ionic crystals for proton conduction. 38,39,[44][45][46] In ] 3− possessing a high water content (both Sm coordinated and in the lattice), and significantly, another characteristic of 1 is the presence of the repetitive array of water molecules in 1D channels. Both features are considered to be beneficial for proton conduction.…”

A supramolecular complex based on poly-Keggin-anion chains: synthesis, structure characterization, and conductivity

“…In title complex, there are three lattice water molecules and the separations between them are enough short to stabilize the excess proton to form such an oligomer as H 7 O 3 ? , so, we think that the excess proton is not localized on the surface of the polyanion [28][29][30][31][32][33].…”

“…In the [PMo 12 O 40 ] 3-unit, the central P atom is surrounded by a cube of eight oxygen atoms with each oxygen site half-occupied. These eight oxygen atoms are all crystallographically disordered, and this case can be found in many compounds [28][29][30][31][32][33]. In complex 1, the bond lengths of P-O and Mo-O are 1.520(9)-1.543 (13) , that there is enough space outside the poly-Keggin-anion chains to admit some small species, such as water molecules or hydronium ions, to transport along the channels.…”